Testudo is a special move of the war tortoise, activated by a testudo scroll. When activated, it temporarily boosts Defence by 9 points. Each use of a Testudo scroll requires 20 special move points and grants 0.7 summoning xp.

When used in conjunction with potions and more scrolls, this effect will NOT stack on top of what has already been boosted. Because of this, even players with a war tortoise following them will typically prefer a defence potion, super defence potion or saradomin brew for raising their defence.